chore(package): update cross-env to version 7.0.2

Closes #72

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
     "babelify": "^10.0.0",
     "browserify": "^16.2.2",
     "chrome-webstore-upload-cli": "^1.1.1",
-    "cross-env": "^5.2.0",
+    "cross-env": "^7.0.2",
     "dot-json": "^1.0.3",
     "event-stream": "^4.0.0",
     "file-saver": "^1.3.3",